Time and/or time-temperature indicating labels may be used in food manufacturing industries to identify food freshness. Time indicating labels may also be used where the label indicates a period of time has expired, such in visitor badge label.
It has long been known to manufacturers and distributors that the shelf life of perishable goods such as foodstuffs is a function of both the time and the temperature at which such goods are stored.
There is a need to monitor and indicate time-temperature exposure of food, so that both merchants and consumers can be assured the food has been stored and refrigerated properly prior to sale and/or use. It is well known that food degrades faster at higher temperatures than at lower temperatures, and that the time of exposure to such higher temperatures strongly relates to the degree of degradation resulting from such exposure.
Many manufacturers place expiration dates on food packaging in an attempt to provide an indication of the useful life of the foodstuff. However, these dates are based on an assumption that the foodstuff is stored under proper conditions, or at least within an estimated range of conditions. In addition, many manufacturers place “sell-by” dates, rather than expiration dates, on food packaging. Sell-by dates provide even less indication of the useful life of a foodstuff, since consumers may assume that the foodstuff remains useable for some time period following the sell-by date.
Both expiration and sell-by date indications break down if the foodstuff is exposed to temperatures higher than expected during the time period prior to the printed expiration or sell-by date. In such case, the food item may have been exposed to spoiling temperatures prior to the marked date, but the retailer or consumer would be misled into thinking the foodstuff was still acceptable. Thus, the need for a time-temperature indicating label has been long standing and continues.
To be useful, a time-temperature indicating label should provide its indication of expiration at approximately the same time as the food is expected to no longer be acceptable. Different foodstuffs have different tolerances for exposure to higher than normal temperatures. Thus, it is necessary to adjust the rate at which the time-temperature indicating label changes color or otherwise indicates that an unacceptable time or temperature has been reached. It is desirable to be able to make such adjustments while changing a minimum of the manufacturing parameters and while maintaining a consistent product, in appearance, usability and function.
A number of devices have been proposed for use as a time-temperature indicating label. However, many of these devices suffer from defects such as being unduly complicated or expensive to manufacture, or the device itself being subject to degradation over time and temperature exposure.
The present invention is intended to provide a solution to the long-standing problems of providing an indication of the exposure of foodstuffs to unacceptable time and/or temperature conditions.
Name badges have been constructed in many different ways for various purposes. One common concern is that a name badge could be re-used at a later date by an un-authorized user, granting them access to a site or specific locations within a site when it is not appropriate, creating a breech in security. One method of addressing this concern is through time indicating name badges, whereby some or all of the badge changes color within a set time period after activation in order to indicate that the badge has expired. Typically this color change occurs within 24 hours after it has been activated. Activation typically consists of creating an adhesive bond between two specially designed surfaces, allowing for either a gradual migration of (or a chemical reaction between) one or more elements within one or both of the surfaces to create the color change over time. All known prior art time sensitive name badges are provided with generic preformatted text (for example, the word “Visitor” printed across the top of the badge), and are designed to be hand-written. The current prior art cannot be run through any commonly available printers (for example laser or inkjet printers) in order to produce a more professional and customized appearance. The present invention is designed to provide time indicating badges that can be printed by the user in a commonly available (e.g., laser or inkjet) printer.